PB666

Gravity is a reflection of Inertia. You have to think of gravity as the way inertial particles behave as the pass close to energy containing regions of space (e = mc2). Since energy and mass can be interchanged then you have conservation of gravity. Lets not forget that antiparticles are composed of quantum elements. In a closed QM system Energy is always (always, always) conserved. Did I say always, I meant to say always. Since antiparticles must follow conservation of energy in their creation and since gravity can be described by general relativity as a reflection of e = mc2 the there is assumption that in a closed system if a form of energy is converted to anti-particles, for energy to be conserved at every level then the gravity should remain constant. The only way you could possibly change this is, for instance a closed systems so large that two events in the system create waves in space-time, and in that case the energy in the systems goes into space-time fluctuations itself and can only be measured external to the system. Fortunately for scientist there is no closed system that deals with that level of mass. The issue of gravity is not whether particles choose to or not to behave in accord with warping of space-time, but how does space-time warp under the extreme variations of conditions possible in the universe, particularly in the vast emptiness of space, or underconditions with quantum scale is so small that sub-resolution behaviors apply.

Yeah, its a problem, but Boca Chica might allows more launches. Problem here is that will the F9 launch from BC. But if they had several launch sites spread far enough apart they could launch twice in one day. Rememeber they said they wanted 5/month . . . 60 per year, if thats split between CC and V thats 30 each. So if the USAF is limiting them to 48 that means 18 for non spaceX at CC. They must have some sort of work-around planned.

Lol, this is what you want a living quarter made out of the inside of a rocket that didn't pass inspection.

The vibration and stretch forces are quite intense, if you have ridden on these bullet trains you would know this. A 787 only experiences stretching forces relative to ambient along the length, a bullet train experiences both compression and inflation forces and the changes occur very rapidly measured in millesonds. Its not an issue of how much force, but given the materials you decided to use and the number of times and how rapidly they are stretched. . . . and via stress testing on the material shows how much more strength needs to be added. An excellent example is a centrifuge rotor. At the beginning of its life you can spin at maximum RPM. Howver the faster you spin it its ages as a function of the square of the speed. At some point the rotir begins to strech and becomes unbalanced. If you never spin the rotor below 85% of its rated RPM then it can be used until the materials themselves (i.e corrosion) degrade. But the rotor ages with expansion contraction events. A rocket is likely never to go through MaxQ 100 times or a 1000 times. A bullet train may reach its extremes 100 times a day. The point about SpaceX is that they have access to NASAs science. In addition they are willing to experiment with various settings. Again, who has done 1000s of launches? They may not have the data, but they clarly have enough engineers and scientist to figure it out. Again these are for decisions that can be made in the operations around Earth. As we know they have used rockets that can be easily used for any type of testing, including sounding rockets. The problem regards testing with regard to Mars and details of Mars that are nit easily reproduced on Earth, when you subject is 3 to 21 months away it does not easily accessed, then it means more testing on Earth is required. They need to be able to make several launches in the range.

You could theoretically make several small plane changes with one BFR upper stage. And the problem here economically is that the more sateelites per launch, the S2 costs start becoming trivial. Since there are going to be competitors you whats going to get as many functional satellites as possible as a driving force for business growth. Again planting all satellites on a single plane or few close planes is not beneficial to the demand side of the business.

Waking up at 3 am and having that mug staring in your face definitely would not cause alot of stress?

What about lithium ion battery explosions in the avionics bay? Don't minimize the scientific prowess of SpaceX they are already the leading sxpert on atmosperic reentry and propsive landings. This assumption is that there is no science in the engineering, thats a false assumption. I should point out one other thing; if they are really looking at shockwave and material stress, your focus should be on the highest speed bullet trains, as for example going through a tunnels whose walls are half a meter from the trains skin at half the speed of sound and doing this every 5 minutes. Changes of pressure steep higher are much more frequent.

The satellites have different orbits. For example you would put equitorial and polar orbiting satellites on the same launch. Cape canaveral affords a 28.3' inclination, but the ascending node rotates along a 360 degree axis, so that if you wait seperate launches by T*2pi/24h - n2pi/24h you can have two launches with orbital inclinations of 56.3' relative inclination. Indeed this is a minimum, for leo communication satellites you may want to leave at a 45' bearing at launch to cover more of the globes surface at close range. The assumption here is this. For any orbit you want many satellites, but with any orbit you can station satellites by slighlty altering apogees and then reducing apogee when its perigee position approximates its station. But for an immediately functioning satellite network filling all the stations of one orbit makes no sense, because then your network provides access twice a day for a brief period of time. Its somewhat more intelligent to stagger the ascending nodes of the launch e.g 0, 180, 90, 270, 45, 135, 225, 315, .......... Well, that would be a problem with the launch phase. The orbiter would be exposed to space weather but the tanks would not be. The extremes of cryogenics can be partially eliminated simply by placing a two-stage refridgerant line into the tank and constantly keeping the tank cold. I think that if you get 10 launches out of the launch phase the marginal gain utility of the next 10 launches drops and the trend continues as such that only if the market is extremely competitive do you want to risk failure by extending the launches.

delete your facebook app. http://www.newsweek.com/facebook-stress-cortisol-social-media-health-break-quit-871521 The drawback is you have facebook withdrawal and have a lower sense of being.

I think they are probably referring to the excitation frequencies.

http://bigthink.com/news/study-men-significantly-more-likely-to-overestimate-their-own-intelligence-2

Who would have guessed? https://www.inquisitr.com/4858552/a-new-study-conducted-at-cern-has-revealed-the-color-of-antimatter/

What happened to building everything from carbon fiber

You seem to be forgetting we've never landed anything over 3 tons and they are trying to land something a magnitude heavier and that there is a long list of Mars cursed mission. The curse of Mars is ignorance.

Hah! You know NASA is designed an Aerobraking (inflatable) for future missions to Mars, and they have tested this at least a few times in Earths atmosphere (with failures). SpaceX has not tested any sounding rockets based on any BFR design, downscaled or otherwise. "Design subject to change" The whole rocket design is based on expected aerodynamic performance in Martian atmosphere, and yet they have done no testing. There is a zero percent chance the current design will stick into production. They may not even be able to produce it in the Port of LA and end up having to build a facility to assemble subs in Boca Chica . . . . . thats the current level of planning for BFR.

Well can the Royal Society really be fair judge of what a 13 yo ukranian boy says. I bet they can't even figure out what their own 13 yo sons are saying.

I have been using 90% of S1 fuel till S1/S2 sep. I expect one of the things block 5 will attempt to do is to get that number up.

Dal could edit the link to make it a std hyperlink, i generally dont click on those links. Well the F9 comes very close to the stated PL to LEO

No doubt, ULA has alot of fuzzy stat rockets themselves, i think i have mentioned that before in critique. Go back to the thread about RL10b-2 in which i was complaining about the high cosine losses. But this was a SpaceX thread and i was focusing on their claims. While i have not commented on their stats on their livery, i have a mental note on some of the fluffiness and untested systems of their livery. Not too long after that ULA claims they are going to use RL10c-'x' for the exact reason of my critique, they sacrifices 15 ISP unit to provide space for 4 engines with 3.8 times the thrust that one b2 could provide. But i am glad you brought the point, but there is one difference, ULA basically solves all of the problems with virtually any sized payloads by using the somewhat inefficient RS25-E/F as second stage engine. They have, with a more efficient cost per thrust unit, a substitute for any payload you can imagine.

if they cannot put 60t of weight on top than you have to put an asterisks by the claim of 62t to orbit, otherwise DAL59 or someone of that thinking is going to twist that into a belief that they actually can push a PL (say H2/O2 . . .or .. .unobtainium) into LEO. This is actually a double asterisks because it likely a claim based on B5 performance, a rocket that has not flown. As I said if the increased the performance of the engines, including M1D vacuum engine, then (see below at worst case scenario a 13% increase in engine performance converts no gain in horizontal velocity into a 50% gain of velocity relative to a flat trajectory along an isoquant). Remember, I made the claim in the beginning that there were fuzzy stats . . fuzzy factoids. That claim of 62t to orbit is clearly a fuzzy fact even by your own statements. Secondarily, if you are pushing S1 trajectory to 2.5Mm above the earth simply to give S2 long enough time to circularize then its no longer 62t to LEO, its something else to something else. Lets go backward with the facts. If you are 99/100% to orbit (tangential component of velocity) you only need what. 0.02TWR on mostly a flat trajectory (just to hold isoquant, 100% cosine loss). With a cosine loss of 0.5 you need 0.023TWR (adjust TWR to reflect gravity at altitude) 98/100% 0.0396TWR, 0.045TWR 50% loss 90/100% 0.19%TWR, 0.219 80/100% 0.36%TWR, 0.414 (this is what 62t to orbit w 60/100% 0.64%TWR <------ 5000 m/s, 0.736TWR for 50% cosine loss (This is approximately what M1D on last FH launch delivered at its start up burn. The craft was losing some but not a horrific amount of vertical velocity. 40/100% 0.84%TWR <------ 3120 m/s, 0.966TWR for 50% cosine loss Just going by this the S1/S2 separation would have had to occur going 2000 m/s faster than FH#1 S1/S2 sep. Cosine losses mean that thrust is given to gravity and not into kinetic energy (whether it be height or hoovering). If you are significantly giving thrust to gravity then you have inadequate thrust to make it to desired orbit, If you devote sufficient enough S1 thrust to generation of apoapsis, the it translates to a loss of horizontal velocity in the S2 which means a greater amount of cosine losses. If you are playing with TWR significantly below the tabulated values then your rocket engine will have significant cosine loses. Centaur used hydrolox, which has ISP in the 460 range, they can afford some cosine losses. But what we are talking about is a strict 200 km LEO orbit, not some elliptoid shaped thing. While this may seem trivial, the ability to convert thrust into energy is dependent on speed. (Why I keep reposting the physics basics over and over again). E = F * d. The faster you travel they greater distance that is covered when force is applied. Ideally if you want to go interplanetary with a massive amount of weight, the best place to make that push is from as low an orbit as possible in which the loss of energy due to drag is less than the loss of energy due to loss of orbital velocity of a higher orbit. You can of course kick out of an elliptical orbit, but our metric here is not that, the metric is what mass was delivered to that ideal LEO. The logic for this is this; lets assume that orbital boost is based on a ~325 ISP system. Your payload is a 460 ISP system, it makes less sense to put the PL into an elliptoid orbit rather than handing more PL mass to so that the more efficient PL can kick to higher orbit. The Centaur _HAS_ ISP of 460, so that its ellipsoid is only a partial loss of energy if it pushes out from the ellipsoid . . and its still better off than M1D because it had higher ISP during the circularization part of its burn. M1D to achieve its claim needs to efficiently place that 62t in an LEO orbit so that the vehicles unobtainium based fuel system can send it to its interplanetary destination. Why would anyone want a 62t payload . . . . one particular reason is to used that PLs propulsion system to drive out an interplanetary orbit. Conserving the fuel for one earth orbit and a burn outward (assuming that the launch occurred from an optimal launch to inclination) then a powerful enough second stage to push to LEO and hold at LEO just long enough to intercept the outbound burn point, followed by a transfer burn (as part of the PL 62t).

What impeccable logic! Lets compare something that exists with something that doesn't exist. Im going to compare Star Treks Voyager with NASA's voyager. Obviously the star trek voyager wins the TV ratings contest, the mileage contest goes to the real one. Engineering is both a theoretical and empirical science. Most of the structural properties are based on observations. Steel is not a natural compound, its manmade (charcoal and iron slag). The same is true with brass and the aluminum alloy that spacecraft are made out of. If you want to know how an engineered systems performs you have to build it. NASA has testing grounds, SpaceX has testing grounds. _______ thinks testing is superfluous, just dream, build and it will fly . . .thats good enough.

Then that's why we are arguing vaporware all the time and its acceptable to do this, it creates an open standard. Aside from that Saturn V with its many stages could roughly approximate an LEO on an abort mode. I would very seriously doubt that SpaceX could haul 62 tons into LEO, other than as part of fuel in its second stage. If you can show me some kind of evidence to the contrary I would be happy to change my opinion. I took their telemetry from the FH launch and looked many ways at it. If we estimate second stage mass with payload of 110 t, and we added 62t of payload on top of that then at 172 tons the acceleration of S2 at engine fire is something like 7 m/s * 110/172 = 4.4 m/s that's less than 1/2g of acceleration. Again this is with block 3 and block 4. There is a claim that block 5 has more power and more dV which if true changes that but my stats on engine performance come from February of this year. Just the very fact of placing 62t on top of the second stage would require some sort of S2 and S1 redesign. 62t to LEO is nothing more than a half dressed woman in lingerie trying to sell Mercurys.

As i said it was dubious, remember, but my point was SpaceX said they could do it, this is misleading if the intent really is to increase weight to GTO. You guys placed this as fit into fairing issue.. What i say its not a fairing issue, SpaceX does not want to get into dealing with full crylox systems. Based on that they really are not interested in delivering anything 62 t to LEO. . . . . . . .this is more about fuzzy stats from unproven configurations of spacecraft, not about what I think they should do. . . . .its about what they said they can do but that everyone knows is unlikely to ever be done. You cannot really rely on this kind of company publicity. Again we are having a debate about what is proven and what is not. Why we are debating this issue is that those that support the unproven stats really dont get that the stats are untenable. Its the same thing as SLS EM-1 sitting on the launch pad dec 14th 2019 and NASA and the fed canceling the program, and then arguing for years whether it would have been a great program. Up until the day SLS puts men intonspace its nothing more than unproven stats and a big hole which public money gets thrown into. For spaceX its only a little white lie.

True actually Aggregat 4 , but both V1 and V2 has production problems that had to be circumvented with new technologies.

Irrelevant as usual